Q&A on Integrated Asset Modeling: Exploring Challenges in CCS Projects

Expert insights on pressure drops, compression costs, and modeling strategies

Carbon Capture and Storage (CCS) is a vital technology in reducing greenhouse gas emissions. With power and industry responsible for more than 30% of global CO₂ emissions, the need for CCS solution has bever been more critical.

According to the International Energy Agency (IEA), there is no path to Net Zero without CSS. The IEA forecasts that to reach Net Zero by 2050 CCS will need to contribute for at least 15% of the overall reduction of CO₂ emissions. However, operating CCS pipelines over long distances presents challenges. From pressure drops to chemical interactions, optimizing systems for technical feasibility and economic sustainability is key to technical and economic feasibility of CCS projects.

In this Q&A, we explore Integrated Asset Modeling (IAM) and its application in CCS. Building on insight from the Importance of an IAM in CCS Applications webinar, we address key questions about pressure management, software capabilities, and operational challenges.

Q1: What mitigation strategies does IAM recommend for handling pressure drops over long transportation distances?

Answer 1: IAM focuses on maintaining operations within the safe envelope. Strategies include:

Correct sizing and operating conditions Align pipeline diameter, inlet pressure, and flow rates for smooth operation, to avoid excessive pressure or cooling that may cause the drop-out of liquid phases or other flow assurance issues.
Operate at High Pressure Supercritical conditions minimize pressure losses but require significant energy for compression. For example, the Porthos compressor station operates at 130 bar, with higher pressures expected as capacity grows.
Leverage Integrated Asset Models Assess how changes in reservoir pressure or other factors impact operating conditions ensure facilities adapt during over time. Through an integrated model of the facilities, which includes flow assurance and asset integrity aspects, we can identify risks and develop mitigating strategies.

While high-pressure operation is advisable, it can be costly or difficult to achieve, due to the need for powerful compressors. In some conditions, heating the fluid before the inlet of the flowline or at the wellhead before injection may be a more agile and achievable approach, as the heating may be required only for a certain period of time.

Q2: Does Maximus IAM software only use tank models, or does it incorporate 3D reservoir models?

Answer 2: Currently, Maximus^® models the reservoir like a tank, for simple material balance calculations, or via production profiles. Work is underway to link Maximus with a 3D reservoir simulator to evaluate workflow and output. This integration presents challenges:

Specialized Expertise 3D modeling requires geological and transport in porous and fractured media knowledge.
Time-Intensive Building and running detailed 3D reservoir models is complex and may not align with Maximus’s focus on flow assurance and asset integrity.

While the feasibility of a direct integration of full 3D models may be limited, potential applications and benefits of this linkage are being evaluated.

Figure 1. CO2 phase management (2-phase flow)

Q3: How does Maximus handle potential chemical interactions between CO₂ and impurities?

Answer 3: Impurities in the CO₂ stream pose challenges:

Current Capabilities Multiflash^® software within Maximus focuses on thermodynamics, not chemical reactions. This ensures fast and reliable calculations for steady-state operations, as shown in Figure 1.
Future Outlook Work is underway to develop a framework to extend Multiflash to reactive components to check for compositional changes.
Real-Time Monitoring In real field operations, online Gas Chromatography analyzers will likely be in place to detect changes in composition at various points in the process upstream, offering a way to monitor reactions and identifying potential risks associated with it.

This remains an ongoing area of research for CCS applications.

Figure 2. CO2– rich fluid properties

Q4: What are the capabilities for phase envelope calculations with high water content and Liquid-Liquid-Vapor (LLV) calculations?

Answer 4: CCS compositions are aggressively dehydrated to avoid water drop-out and corrosion. However, Figure 2 illustrates how Multiflash models complex phase behavior, including:

Modeling various compositions and rich phase behaviors.
Predicting water phase formation at low temperatures, even with minimal water.
Model’s parameters are tuned to Vapor-Liquid Equilibrium (VLE) data to ensure accurate predictions of solubility and phase behavior.

Q5: Can you comment on the costs of compression?

Answer 5: Compression costs impact the feasibility of CCS projects. Considerations include:

Compressor Duty Operating at pressures between 91and 200 bar minimizes the risk of liquid drop-out but require significant energy and CAPEX for large compressors.
Trade-off Analysis Balancing compression with alternatives like heating is needed to optimize energy use, emissions, and costs.
KBC’s Capabilities Solutions like Petro-SIM^® evaluate CAPEX/OPEX trade-offs and overall energy management for CCS systems.

Modeling these trade-offs early ensure projects are within budget and sustainable.

Q6: How does IAM address the challenges of limited field data in CCS modeling?

Answer 6: Little operating data in CCS systems introduces uncertainties. To address this:

Focus on Single-Phase Operations Flow correlations, in terms of pressure drop, are reliable when the viscosity data is correct. There’s uncertainty around the properties of two- or three-phase flows for CCS applications.
Address Knowledge Gaps Multiphase flow dynamics in typical phases (e.g., water, vapors, impurities) are being studied through Joint Industry Projects.

Staying within single-phase conditions reduces uncertainties and improves reliability as real-world data becomes available.

Q7: How do you model transient scenarios like pipeline restarts?

Answer 7: Transient scenarios, such as pipeline restarts and shutdowns, require dynamic simulation tools. Here’s what’s available:

Maximus Software Focuses on steady-state modeling and field life, using time steps of weeks or months. It is effective for life-of-field analysis but insufficient for transient scenarios.
Dynamic Simulators Tools like Petro-SIM, OLGA, LedaFlow, and Turbulent Flux excel at modeling restarts, shutdowns, and flow transients. They capture the dynamics of fluid flow, pressure changes, and temperature profiles over time.

While steady-state tools are ideal for long-term predictions and daily averaged balances, dynamic simulators ensure safe and reliable operations during unsteady conditions.

Conclusion

This Q&A highlights the importance of IAM in addressing CCS complexities. From pressure drops to compression costs, IAM tools like Maximus and Multiflash software offer valuable insights for project optimization. These tools enable engineers and decision-makers to simulate various scenarios, predict potential challenges, and develop effective solutions before implementation.

As projects scale and real-world data become available, continued research will enhance model accuracy to ensure the long-term success and sustainability of CCS projects. By understanding and implementing IAM, we can improve the efficiency and effectiveness of CCS systems. This progress is essential in our journey towards achieving net-zero emissions and, ultimately, in Bringing Decarbonization to Life^®.

For more insight on the importance of IAM in optimizing CCS projects, please watch the Importance of an IAM in CCS Applications webinar.